Birds
In birds the cloaca is the terminal chamber of the gastrointestinal and urogenital systems, opening at the vent. Among falconers the word vent is also a verb meaning "to defecate". Excretory systems with analogous purpose in certain invertebrates are also sometimes referred to as "cloacae".
Birds also reproduce with this organ; this is known as a cloacal kiss. Birds that mate using this method touch their cloacae together, in some species for only a few seconds, sufficient time for sperm to be transferred from the male to the female. The reproductive system must be re-engorged prior to the mating season of each species. Such regeneration usually takes about a month. Birds generally produce one batch of eggs per year, but they will produce another if the first is taken away. For some birds, such as ostriches, cassowaries, kiwis, geese, and some species of swans and ducks, the males do not use the cloaca for reproduction but have a phallus. In those, the penis helps ensure that water does not wash away the male's sperm during copulation.
One study has looked into birds that use their cloaca for cooling (see urohidrosis).
Read more about this topic: Cloaca
Famous quotes containing the word birds:
“The birds that came to it through the air
At broken windows flew out and in,
Their murmur more like the sigh we sigh
From too much dwelling on what has been.”
—Robert Frost (1874–1963)
“When you have shot one bird flying you have shot all birds flying. They are all different and they fly in different ways but the sensation is the same and the last one is as good as the first.”
—Ernest Hemingway (1899–1961)
“While he hears in every spring
How the birds do chirp and sing:
Or before the hounds in cry
See the hare go stealing by:
Or along the shallow brook,
Angling with a baited hook,
See the fishes leap and play
In a blessed sunny day:”
—Nicholas Breton (1542–1626)